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626 lines
15 KiB
626 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* GPIO Testing Device Driver |
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* |
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* Copyright (C) 2014 Kamlakant Patel <[email protected]> |
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* Copyright (C) 2015-2016 Bamvor Jian Zhang <[email protected]> |
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* Copyright (C) 2017 Bartosz Golaszewski <[email protected]> |
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*/ |
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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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|
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#include <linux/debugfs.h> |
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#include <linux/gpio/driver.h> |
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#include <linux/interrupt.h> |
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#include <linux/irq.h> |
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#include <linux/irq_sim.h> |
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#include <linux/irqdomain.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/property.h> |
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#include <linux/slab.h> |
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#include <linux/string_helpers.h> |
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#include <linux/uaccess.h> |
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#include "gpiolib.h" |
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#define GPIO_MOCKUP_MAX_GC 10 |
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/* |
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* We're storing two values per chip: the GPIO base and the number |
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* of GPIO lines. |
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*/ |
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#define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2) |
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/* Maximum of four properties + the sentinel. */ |
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#define GPIO_MOCKUP_MAX_PROP 5 |
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|
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/* |
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* struct gpio_pin_status - structure describing a GPIO status |
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* @dir: Configures direction of gpio as "in" or "out" |
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* @value: Configures status of the gpio as 0(low) or 1(high) |
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*/ |
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struct gpio_mockup_line_status { |
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int dir; |
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int value; |
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int pull; |
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}; |
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struct gpio_mockup_chip { |
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struct gpio_chip gc; |
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struct gpio_mockup_line_status *lines; |
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struct irq_domain *irq_sim_domain; |
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struct dentry *dbg_dir; |
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struct mutex lock; |
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}; |
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struct gpio_mockup_dbgfs_private { |
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struct gpio_mockup_chip *chip; |
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struct gpio_desc *desc; |
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unsigned int offset; |
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}; |
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static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES]; |
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static int gpio_mockup_num_ranges; |
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module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400); |
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static bool gpio_mockup_named_lines; |
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module_param_named(gpio_mockup_named_lines, |
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gpio_mockup_named_lines, bool, 0400); |
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static struct dentry *gpio_mockup_dbg_dir; |
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static int gpio_mockup_range_base(unsigned int index) |
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{ |
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return gpio_mockup_ranges[index * 2]; |
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} |
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static int gpio_mockup_range_ngpio(unsigned int index) |
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{ |
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return gpio_mockup_ranges[index * 2 + 1]; |
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} |
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static int __gpio_mockup_get(struct gpio_mockup_chip *chip, |
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unsigned int offset) |
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{ |
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return chip->lines[offset].value; |
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} |
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static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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int val; |
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mutex_lock(&chip->lock); |
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val = __gpio_mockup_get(chip, offset); |
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mutex_unlock(&chip->lock); |
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return val; |
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} |
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static int gpio_mockup_get_multiple(struct gpio_chip *gc, |
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unsigned long *mask, unsigned long *bits) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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unsigned int bit, val; |
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mutex_lock(&chip->lock); |
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for_each_set_bit(bit, mask, gc->ngpio) { |
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val = __gpio_mockup_get(chip, bit); |
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__assign_bit(bit, bits, val); |
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} |
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mutex_unlock(&chip->lock); |
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return 0; |
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} |
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static void __gpio_mockup_set(struct gpio_mockup_chip *chip, |
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unsigned int offset, int value) |
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{ |
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chip->lines[offset].value = !!value; |
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} |
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static void gpio_mockup_set(struct gpio_chip *gc, |
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unsigned int offset, int value) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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mutex_lock(&chip->lock); |
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__gpio_mockup_set(chip, offset, value); |
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mutex_unlock(&chip->lock); |
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} |
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static void gpio_mockup_set_multiple(struct gpio_chip *gc, |
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unsigned long *mask, unsigned long *bits) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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unsigned int bit; |
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mutex_lock(&chip->lock); |
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for_each_set_bit(bit, mask, gc->ngpio) |
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__gpio_mockup_set(chip, bit, test_bit(bit, bits)); |
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mutex_unlock(&chip->lock); |
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} |
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static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip, |
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unsigned int offset, int value) |
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{ |
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struct gpio_chip *gc = &chip->gc; |
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struct gpio_desc *desc = gpiochip_get_desc(gc, offset); |
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int curr, irq, irq_type, ret = 0; |
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mutex_lock(&chip->lock); |
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if (test_bit(FLAG_REQUESTED, &desc->flags) && |
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!test_bit(FLAG_IS_OUT, &desc->flags)) { |
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curr = __gpio_mockup_get(chip, offset); |
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if (curr == value) |
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goto out; |
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irq = irq_find_mapping(chip->irq_sim_domain, offset); |
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if (!irq) |
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/* |
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* This is fine - it just means, nobody is listening |
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* for interrupts on this line, otherwise |
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* irq_create_mapping() would have been called from |
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* the to_irq() callback. |
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*/ |
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goto set_value; |
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irq_type = irq_get_trigger_type(irq); |
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if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) || |
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(value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING))) { |
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ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, |
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true); |
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if (ret) |
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goto out; |
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} |
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} |
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set_value: |
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/* Change the value unless we're actively driving the line. */ |
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if (!test_bit(FLAG_REQUESTED, &desc->flags) || |
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!test_bit(FLAG_IS_OUT, &desc->flags)) |
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__gpio_mockup_set(chip, offset, value); |
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out: |
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chip->lines[offset].pull = value; |
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mutex_unlock(&chip->lock); |
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return ret; |
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} |
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static int gpio_mockup_set_config(struct gpio_chip *gc, |
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unsigned int offset, unsigned long config) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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switch (pinconf_to_config_param(config)) { |
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case PIN_CONFIG_BIAS_PULL_UP: |
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return gpio_mockup_apply_pull(chip, offset, 1); |
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case PIN_CONFIG_BIAS_PULL_DOWN: |
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return gpio_mockup_apply_pull(chip, offset, 0); |
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default: |
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break; |
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} |
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return -ENOTSUPP; |
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} |
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static int gpio_mockup_dirout(struct gpio_chip *gc, |
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unsigned int offset, int value) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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mutex_lock(&chip->lock); |
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chip->lines[offset].dir = GPIO_LINE_DIRECTION_OUT; |
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__gpio_mockup_set(chip, offset, value); |
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mutex_unlock(&chip->lock); |
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return 0; |
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} |
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static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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mutex_lock(&chip->lock); |
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chip->lines[offset].dir = GPIO_LINE_DIRECTION_IN; |
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mutex_unlock(&chip->lock); |
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return 0; |
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} |
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static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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int direction; |
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mutex_lock(&chip->lock); |
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direction = chip->lines[offset].dir; |
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mutex_unlock(&chip->lock); |
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return direction; |
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} |
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static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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return irq_create_mapping(chip->irq_sim_domain, offset); |
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} |
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static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset) |
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{ |
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struct gpio_mockup_chip *chip = gpiochip_get_data(gc); |
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__gpio_mockup_set(chip, offset, chip->lines[offset].pull); |
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} |
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static ssize_t gpio_mockup_debugfs_read(struct file *file, |
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char __user *usr_buf, |
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size_t size, loff_t *ppos) |
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{ |
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struct gpio_mockup_dbgfs_private *priv; |
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struct gpio_mockup_chip *chip; |
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struct seq_file *sfile; |
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struct gpio_chip *gc; |
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int val, cnt; |
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char buf[3]; |
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if (*ppos != 0) |
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return 0; |
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sfile = file->private_data; |
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priv = sfile->private; |
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chip = priv->chip; |
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gc = &chip->gc; |
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val = gpio_mockup_get(gc, priv->offset); |
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cnt = snprintf(buf, sizeof(buf), "%d\n", val); |
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return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt); |
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} |
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static ssize_t gpio_mockup_debugfs_write(struct file *file, |
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const char __user *usr_buf, |
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size_t size, loff_t *ppos) |
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{ |
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struct gpio_mockup_dbgfs_private *priv; |
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int rv, val; |
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struct seq_file *sfile; |
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if (*ppos != 0) |
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return -EINVAL; |
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rv = kstrtoint_from_user(usr_buf, size, 0, &val); |
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if (rv) |
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return rv; |
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if (val != 0 && val != 1) |
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return -EINVAL; |
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sfile = file->private_data; |
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priv = sfile->private; |
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rv = gpio_mockup_apply_pull(priv->chip, priv->offset, val); |
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if (rv) |
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return rv; |
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return size; |
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} |
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static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file) |
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{ |
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return single_open(file, NULL, inode->i_private); |
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} |
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/* |
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* Each mockup chip is represented by a directory named after the chip's device |
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* name under /sys/kernel/debug/gpio-mockup/. Each line is represented by |
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* a file using the line's offset as the name under the chip's directory. |
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* |
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* Reading from the line's file yields the current *value*, writing to the |
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* line's file changes the current *pull*. Default pull for mockup lines is |
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* down. |
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* |
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* Examples: |
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* - when a line pulled down is requested in output mode and driven high, its |
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* value will return to 0 once it's released |
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* - when the line is requested in output mode and driven high, writing 0 to |
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* the corresponding debugfs file will change the pull to down but the |
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* reported value will still be 1 until the line is released |
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* - line requested in input mode always reports the same value as its pull |
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* configuration |
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* - when the line is requested in input mode and monitored for events, writing |
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* the same value to the debugfs file will be a noop, while writing the |
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* opposite value will generate a dummy interrupt with an appropriate edge |
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*/ |
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static const struct file_operations gpio_mockup_debugfs_ops = { |
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.owner = THIS_MODULE, |
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.open = gpio_mockup_debugfs_open, |
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.read = gpio_mockup_debugfs_read, |
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.write = gpio_mockup_debugfs_write, |
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.llseek = no_llseek, |
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.release = single_release, |
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}; |
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static void gpio_mockup_debugfs_setup(struct device *dev, |
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struct gpio_mockup_chip *chip) |
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{ |
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struct gpio_mockup_dbgfs_private *priv; |
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struct gpio_chip *gc; |
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const char *devname; |
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char *name; |
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int i; |
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gc = &chip->gc; |
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devname = dev_name(&gc->gpiodev->dev); |
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chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir); |
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for (i = 0; i < gc->ngpio; i++) { |
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name = devm_kasprintf(dev, GFP_KERNEL, "%d", i); |
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if (!name) |
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return; |
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return; |
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priv->chip = chip; |
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priv->offset = i; |
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priv->desc = gpiochip_get_desc(gc, i); |
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debugfs_create_file(name, 0200, chip->dbg_dir, priv, |
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&gpio_mockup_debugfs_ops); |
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} |
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} |
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static void gpio_mockup_dispose_mappings(void *data) |
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{ |
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struct gpio_mockup_chip *chip = data; |
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struct gpio_chip *gc = &chip->gc; |
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int i, irq; |
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for (i = 0; i < gc->ngpio; i++) { |
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irq = irq_find_mapping(chip->irq_sim_domain, i); |
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if (irq) |
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irq_dispose_mapping(irq); |
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} |
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} |
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static int gpio_mockup_probe(struct platform_device *pdev) |
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{ |
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struct gpio_mockup_chip *chip; |
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struct gpio_chip *gc; |
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struct device *dev; |
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const char *name; |
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int rv, base, i; |
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u16 ngpio; |
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dev = &pdev->dev; |
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rv = device_property_read_u32(dev, "gpio-base", &base); |
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if (rv) |
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base = -1; |
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rv = device_property_read_u16(dev, "nr-gpios", &ngpio); |
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if (rv) |
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return rv; |
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rv = device_property_read_string(dev, "chip-label", &name); |
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if (rv) |
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name = dev_name(dev); |
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chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); |
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if (!chip) |
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return -ENOMEM; |
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mutex_init(&chip->lock); |
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gc = &chip->gc; |
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gc->base = base; |
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gc->ngpio = ngpio; |
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gc->label = name; |
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gc->owner = THIS_MODULE; |
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gc->parent = dev; |
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gc->get = gpio_mockup_get; |
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gc->set = gpio_mockup_set; |
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gc->get_multiple = gpio_mockup_get_multiple; |
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gc->set_multiple = gpio_mockup_set_multiple; |
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gc->direction_output = gpio_mockup_dirout; |
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gc->direction_input = gpio_mockup_dirin; |
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gc->get_direction = gpio_mockup_get_direction; |
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gc->set_config = gpio_mockup_set_config; |
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gc->to_irq = gpio_mockup_to_irq; |
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gc->free = gpio_mockup_free; |
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chip->lines = devm_kcalloc(dev, gc->ngpio, |
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sizeof(*chip->lines), GFP_KERNEL); |
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if (!chip->lines) |
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return -ENOMEM; |
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for (i = 0; i < gc->ngpio; i++) |
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chip->lines[i].dir = GPIO_LINE_DIRECTION_IN; |
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chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL, |
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gc->ngpio); |
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if (IS_ERR(chip->irq_sim_domain)) |
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return PTR_ERR(chip->irq_sim_domain); |
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rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip); |
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if (rv) |
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return rv; |
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rv = devm_gpiochip_add_data(dev, &chip->gc, chip); |
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if (rv) |
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return rv; |
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gpio_mockup_debugfs_setup(dev, chip); |
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return 0; |
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} |
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static const struct of_device_id gpio_mockup_of_match[] = { |
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{ .compatible = "gpio-mockup", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, gpio_mockup_of_match); |
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static struct platform_driver gpio_mockup_driver = { |
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.driver = { |
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.name = "gpio-mockup", |
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.of_match_table = gpio_mockup_of_match, |
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}, |
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.probe = gpio_mockup_probe, |
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}; |
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static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC]; |
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static void gpio_mockup_unregister_pdevs(void) |
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{ |
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struct platform_device *pdev; |
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struct fwnode_handle *fwnode; |
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int i; |
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for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) { |
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pdev = gpio_mockup_pdevs[i]; |
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if (!pdev) |
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continue; |
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fwnode = dev_fwnode(&pdev->dev); |
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platform_device_unregister(pdev); |
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fwnode_remove_software_node(fwnode); |
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} |
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} |
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static __init char **gpio_mockup_make_line_names(const char *label, |
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unsigned int num_lines) |
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{ |
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unsigned int i; |
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char **names; |
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names = kcalloc(num_lines + 1, sizeof(char *), GFP_KERNEL); |
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if (!names) |
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return NULL; |
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for (i = 0; i < num_lines; i++) { |
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names[i] = kasprintf(GFP_KERNEL, "%s-%u", label, i); |
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if (!names[i]) { |
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kfree_strarray(names, i); |
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return NULL; |
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} |
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} |
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return names; |
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} |
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static int __init gpio_mockup_register_chip(int idx) |
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{ |
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struct property_entry properties[GPIO_MOCKUP_MAX_PROP]; |
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struct platform_device_info pdevinfo; |
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struct platform_device *pdev; |
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struct fwnode_handle *fwnode; |
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char **line_names = NULL; |
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char chip_label[32]; |
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int prop = 0, base; |
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u16 ngpio; |
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memset(properties, 0, sizeof(properties)); |
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memset(&pdevinfo, 0, sizeof(pdevinfo)); |
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snprintf(chip_label, sizeof(chip_label), "gpio-mockup-%c", idx + 'A'); |
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properties[prop++] = PROPERTY_ENTRY_STRING("chip-label", chip_label); |
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base = gpio_mockup_range_base(idx); |
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if (base >= 0) |
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properties[prop++] = PROPERTY_ENTRY_U32("gpio-base", base); |
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ngpio = base < 0 ? gpio_mockup_range_ngpio(idx) |
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: gpio_mockup_range_ngpio(idx) - base; |
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properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio); |
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if (gpio_mockup_named_lines) { |
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line_names = gpio_mockup_make_line_names(chip_label, ngpio); |
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if (!line_names) |
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return -ENOMEM; |
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properties[prop++] = PROPERTY_ENTRY_STRING_ARRAY_LEN( |
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"gpio-line-names", line_names, ngpio); |
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} |
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fwnode = fwnode_create_software_node(properties, NULL); |
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if (IS_ERR(fwnode)) |
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return PTR_ERR(fwnode); |
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pdevinfo.name = "gpio-mockup"; |
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pdevinfo.id = idx; |
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pdevinfo.fwnode = fwnode; |
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pdev = platform_device_register_full(&pdevinfo); |
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kfree_strarray(line_names, ngpio); |
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if (IS_ERR(pdev)) { |
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fwnode_remove_software_node(fwnode); |
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pr_err("error registering device"); |
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return PTR_ERR(pdev); |
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} |
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gpio_mockup_pdevs[idx] = pdev; |
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return 0; |
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} |
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|
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static int __init gpio_mockup_init(void) |
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{ |
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int i, num_chips, err; |
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|
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if ((gpio_mockup_num_ranges % 2) || |
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(gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES)) |
|
return -EINVAL; |
|
|
|
/* Each chip is described by two values. */ |
|
num_chips = gpio_mockup_num_ranges / 2; |
|
|
|
/* |
|
* The second value in the <base GPIO - number of GPIOS> pair must |
|
* always be greater than 0. |
|
*/ |
|
for (i = 0; i < num_chips; i++) { |
|
if (gpio_mockup_range_ngpio(i) < 0) |
|
return -EINVAL; |
|
} |
|
|
|
gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL); |
|
|
|
err = platform_driver_register(&gpio_mockup_driver); |
|
if (err) { |
|
pr_err("error registering platform driver\n"); |
|
debugfs_remove_recursive(gpio_mockup_dbg_dir); |
|
return err; |
|
} |
|
|
|
for (i = 0; i < num_chips; i++) { |
|
err = gpio_mockup_register_chip(i); |
|
if (err) { |
|
platform_driver_unregister(&gpio_mockup_driver); |
|
gpio_mockup_unregister_pdevs(); |
|
debugfs_remove_recursive(gpio_mockup_dbg_dir); |
|
return err; |
|
} |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static void __exit gpio_mockup_exit(void) |
|
{ |
|
debugfs_remove_recursive(gpio_mockup_dbg_dir); |
|
platform_driver_unregister(&gpio_mockup_driver); |
|
gpio_mockup_unregister_pdevs(); |
|
} |
|
|
|
module_init(gpio_mockup_init); |
|
module_exit(gpio_mockup_exit); |
|
|
|
MODULE_AUTHOR("Kamlakant Patel <[email protected]>"); |
|
MODULE_AUTHOR("Bamvor Jian Zhang <[email protected]>"); |
|
MODULE_AUTHOR("Bartosz Golaszewski <[email protected]>"); |
|
MODULE_DESCRIPTION("GPIO Testing driver"); |
|
MODULE_LICENSE("GPL v2");
|
|
|